Travelers' diarrhea is the most common travel-related ailment. The cornerstone of prevention is food and water precautions, as outlined below. All travelers should bring along an antibiotic and an antidiarrheal drug to be started promptly if significant diarrhea occurs, defined as three or more loose stools in an 8-hour period or five or more loose stools in a 24-hour period, especially if associated with nausea, vomiting, cramps, fever or blood in the stool. A quinolone antibiotic is usually prescribed: either ciprofloxacin (Cipro)(PDF) 500 mg twice daily or levofloxacin (Levaquin) (PDF) 500 mg once daily for a total of three days. Quinolones are generally well-tolerated, but occasionally cause sun sensitivity and should not be given to children, pregnant women, or anyone with a history of quinolone allergy. Alternative regimens include a three day course of rifaximin (Xifaxan) 200 mg three times daily or azithromycin (Zithromax) 500 mg once daily. Rifaximin should not be used by those with fever or bloody stools and is not approved for pregnant women or those under age 12. Azithromycin should be avoided in those allergic to erythromycin or related antibiotics. An antidiarrheal drug such as loperamide (Imodium) or diphenoxylate (Lomotil) should be taken as needed to slow the frequency of stools, but not enough to stop the bowel movements completely. Diphenoxylate (Lomotil) and loperamide (Imodium) should not be given to children under age two.

Most cases of travelers' diarrhea are mild and do not require either antibiotics or antidiarrheal drugs. Adequate fluid intake is essential.

If diarrhea is severe or bloody, or if fever occurs with shaking chills, or if abdominal pain becomes marked, or if diarrhea persists for more than 72 hours, medical attention should be sought.

Though effective, antibiotics are not recommended prophylactically (i.e. to prevent diarrhea before it occurs) because of the risk of adverse effects, though this approach may be warranted in special situations, such as immunocompromised travelers.

The following are the recommended vaccinations for Phuket:

Hepatitis A vaccine is recommended for all travelers over one year of age. It should be given at least two weeks (preferably four weeks or more) before departure. A booster should be given 6-12 months later to confer long-term immunity. Two vaccines are currently available in the United States: VAQTA (Merck and Co., Inc.) (PDF) and Havrix (GlaxoSmithKline) (PDF). Both are well-tolerated. Side-effects, which are generally mild, may include soreness at the injection site, headache, and malaise.

Certain lots of VAQTA were recalled in December 2001 because some prefilled syringes were found not to contain enough antigen. Those who received VAQTA between August 1999 and December 2001 should go to hepatitis Ato determine whether or not they may require reimmunization.

Older adults, immunocompromised persons, and those with chronic liver disease or other chronic medical conditions who have less than two weeks before departure should receive a single intramuscular dose of immune globulin (0.02 mL/kg) at a separate anatomic injection site in addition to the initial dose of vaccine. Travelers who are less than one year of age or allergic to a vaccine component should receive a single intramuscular dose of immune globulin (see hepatitis A for dosage) in the place of vaccine.

Typhoid vaccine is recommended for all travelers who may eat or drink outside major restaurants and hotels. It is generally given in an oral form (Vivotif Berna) consisting of four capsules taken on alternate days until completed. The capsules should be kept refrigerated and taken with cool liquid. Side-effects are uncommon and may include abdominal discomfort, nausea, rash or hives. The alternative is an injectable polysaccharide vaccine (Typhim Vi; Aventis Pasteur Inc.) (PDF), given as a single dose. Adverse reactions, which are uncommon, may include discomfort at the injection site, fever and headache. The oral vaccine is approved for travelers at least six years old, whereas the injectable vaccine is approved for those over age two. There are no data concerning the safety of typhoid vaccine during pregnancy. The injectable vaccine (Typhim Vi) is probably preferable to the oral vaccine in pregnant and immunocompromised travelers.

Yellow fever vaccine is required for all travelers over one year of age arriving from a yellow-fever-infected country in Africa or the Americas, but is not recommended or required otherwise. Yellow fever vaccine (YF-VAX; Aventis Pasteur Inc.) (PDF) must be administered at an approved yellow fever vaccination center, which will give each vaccinee a fully validated International Certificate of Vaccination. Yellow fever vaccine should not in general be given to those who are younger than nine months of age, pregnant, immunocompromised, or allergic to eggs. It should also not be given to those with a history of thymus disease or thymectomy.

Tetanus-diphtheria vaccine is recommended for all travelers who have not received a tetanus-diphtheria immunization within the last 10 years.

Measles-mumps-rubella vaccine: two doses are recommended (if not previously given) for all travelers born after 1956, unless blood tests show immunity. Many adults born after 1956 and before 1970 received only one vaccination against measles, mumps, and rubella as children and should be given a second dose before travel. MMR vaccine should not be given to pregnant or severely immunocompromised individuals.

Dengue fever is highly prevalent in Thailand. An unusually large number of cases was reported in 1998, possibly related to climatic changes due to El Nino. Dengue is transmitted by Aedes mosquitoes, which bite primarily in the daytime and favor densely populated areas, though they also inhabit rural environments. No vaccine is available at this time. Insect protection measures, as outlined below, are advised.

HIV (human immunodeficiency virus) infection is reported, but travelers are not at risk unless they have unprotected sexual contacts or receive injections or blood transfusions.

Do not drink tap water unless it has been boiled, filtered, or chemically disinfected. Do not drink unbottled beverages or drinks with ice. Do not eat fruits or vegetables unless they have been peeled or cooked. Avoid cooked foods that are no longer piping hot. Cooked foods that have been left at room temperature are particularly hazardous. Avoid unpasteurized milk and any products that might have been made from unpasteurized milk, such as ice cream. Avoid food and beverages obtained from street vendors. Do not eat raw or undercooked meat or fish. Some types of fish may contain poisonous biotoxins even when cooked. Barracuda in particular should never be eaten. Other fish that may contain toxins include red snapper, grouper, amberjack, sea bass, and a large number of tropical reef fish.

All travelers should bring along an antibiotic and an antidiarrheal drug to be started promptly if significant diarrhea occurs, defined as three or more loose stools in an 8-hour period or five or more loose stools in a 24-hour period, especially if accompanied by nausea, vomiting, cramps, fever or blood in the stool. Antibiotics which have been shown to be effective include ciprofloxacin (Cipro), levofloxacin (Levaquin), rifaximin (Xifaxan), or azithromycin (Zithromax). Either loperamide (Imodium) or diphenoxylate (Lomotil) should be taken in addition to the antibiotic to reduce diarrhea and prevent dehydration.

If diarrhea is severe or bloody, or if fever occurs with shaking chills, or if abdominal pain becomes marked, or if diarrhea persists for more than 72 hours, medical attention should be sought.

Wear long sleeves, long pants, hats and shoes (rather than sandals). Apply insect repellents containing 25-50% DEET (N,N-diethyl-3-methylbenzamide) or 20% picaridin (Bayrepel) to exposed skin (but not to the eyes, mouth, or open wounds). DEET may also be applied to clothing. Products with a lower concentration of either repellent need to be repplied more frequently. Products with a higher concentration of DEET carry an increased risk of neurologic toxicity, especially in children, without any additional benefit. Do not use either DEET or picaridin on children less than two years of age. For additional protection, apply permethrin-containing compounds to clothing, shoes, and bed nets. Permethrin-treated clothing appears to have little toxicity. Don't sleep with the window open unless there is a screen. If sleeping outdoors or in an accomodation that allows entry of mosquitoes, use a bed net, preferably impregnated with insect repellent, with edges tucked in under the mattress. The mesh size should be less than 1.5 mm. If the sleeping area is not otherwise protected, use a mosquito coil, which fills the room with insecticide through the night.

Bring adequate supplies of all medications in their original containers, clearly labeled. Carry a signed, dated letter from the primary physician describing all medical conditions and listing all medications, including generic names. If carrying syringes or needles, be sure to carry a physician's letter documenting their medical necessity.Pack all medications in hand luggage. Carry a duplicate supply in the checked luggage. If you wear glasses or contacts, bring an extra pair. If you have significant allergies or chronic medical problems, wear a medical alert bracelet.

Make sure your health insurance covers you for medical expenses abroad. If not, supplemental insurance for overseas coverage, including possible evacuation, should be seriously considered. If illness occurs while abroad, medical expenses including evacuation may run to tens of thousands of dollars. For a list of travel insurance and air ambulance companies, go to Medical Information for Americans Traveling Abroad on the U.S. State Department website. Bring your insurance card, claim forms, and any other relevant insurance documents. Before departure, determine whether your insurance plan will make payments directly to providers or reimburse you later for overseas health expenditures. The Medicare and Medicaid programs do not pay for medical services outside the United States.

Pack a personal medical kit, customized for your trip (see description). Take appropriate measures to prevent motion sickness and jet lag, discussed elsewhere. On long flights, be sure to walk around the cabin, contract your leg muscles periodically, and drink plenty of fluids to prevent blood clots in the legs. For those at high risk for blood clots, consider wearing compression stockings.

Avoid contact with stray dogs and other animals. If an animal bites or scratches you, clean the wound with large amounts of soap and water and contact local health authorities immediately. Wear sun block regularly when needed. Use condoms for all sexual encounters. Ride only in motor vehicles with seat belts. Do not ride on motorcycles.

The following vaccines are strongly recommended for all travelers to Phuket and other tsunami-affected areas:

• Hepatitis A
• Hepatitis B
• Typhoid (oral or injectable)
• Tetanus-diphtheria (booster every 10 years; cases of tetanus have been reported among tsunami survivors)
• Cholera (available in Canada and many European countries, but not marketed in the U.S.)
• Japanese encephalitis (three doses over 2-4 weeks)
• Rabies (requires at least 3 weeks to complete; no benefit from incomplete vaccination)
• Influenza (if injectable vaccine not available, nasal vaccine is alternative for healthy people between the ages of 5 and 50)
• Measles (for travelers born after 1956 who do not have either a history of two documented measles immunizations or a blood test showing immunity. Many adults who had only one vaccination show immunity when tested and do not need the second vaccination.)

All travelers to tsunami-affected areas should also bring along the following:

• Malaria prophylaxis (either Lariam, Malarone, or doxycycline; the CDC suggests that doxycycline may be preferable because it may prevent other infections, such as cholera and leptospirosis)
• A quinolone antibiotic, such as Levaquin or Cipro (unless pregnant or allergic; effective against travelers's diarrhea, as well as cholera and typhoid; also effective against skin infections caused by Pseudomonas and Aeromonas, which have been reported from tsunami-affected areas)
• Doxycycline (unless pregnant or allergic; effective against leptospirosis, cholera, plague, and many respiratory infections)
• Tamiflu (effective against influenza; may also be effective against avian influenza)
• Loperamide (Imodium) or diphenoxylate (Lomotil) (in case of diarrhea)
• Insect repellent (25-35% DEET for adults)
• A fully stocked medical kit (essential)

The recommendations outlined above regarding food and water precautions and insect protection measures must be scrupulously followed at all times.

Snake bites are more likely after flooding and other natural disasters. Never attempt to kill or handle a snake. In the event of a venomous snake bite, move the victim a safe distance from the snake and place him or her at rest, with the affected extremity immobilized and kept below the level of the heart. Remove constrictive clothing and jewelry. Apply a pressure bandage which does not impede blood flow. Avoid tourniquets, which are no longer recommended. Bring the victim immediately to the nearest medical facility for administration of antivenom and supportive care. To reduce the risk of snake bites, wear boots and long pants and avoid perfumes and cologne.

For further information, go to Tsunami Disaster: Interim Guidance for Travelers on the CDC website.

Medical treatment is generally adequate throughout Thailand, and is quite good in Bangkok, where excellent facilities exist for routine, long-term and emergency health care. Thailand has been experiencing an epidemic of HIV infection and AIDS. Heterosexual transmission accounts for most HIV infections, and HIV is common among prostitutes of both sexes, as well as among injection drug users. HIV infections among men who have sex with men appear to be on the rise. Additionally, alcoholic beverages, medications and drugs may be more potent or of a different composition than similar ones in the United States. Several U.S. citizen tourists die in Thailand each year of apparent premature heart attacks after drinking alcohol or using drugs.

Helpful maps are available in the University of Texas Perry-Castaneda Map Collection and the United Nations map library. If you have the name of the town or city you'll be visiting and need to know which state or province it's in, you might find your answer in the Getty Thesaurus of Geographic Names.

Americans living in or visiting Thailand are encouraged to register, either online, or in person at the Consular Section of the U.S. Embassy in Bangkok or the U.S. Consulate General in Chiang Mai. At both locations updated information on travel and security in Thailand is available. The Consular Section of the U.S. Embassy is located at 95 Wireless Road in Bangkok; the U.S. mailing address is APO AP 96546-0001. The central switchboard number is (66-2) 205-4000; the American Citizen Services Unit number is (66-2) 205-4049; and the fax number is (66-2) 205-4103. The web site for the U.S. Embassy is http://bangkok.usembassy.gov/ . American citizens can register online via the web site. Questions regarding American Citizens Services can be submitted by E-mail to acsbkk@state.gov. The U.S. Consulate General in Chiang Mai is located at 387 Wichayanond Road; the U.S. mailing address is Box C, APO AP 96546. The telephone number is (66-53) 252-629 and the fax number is (66-53) 252-633.